Tissue eosinophilia is a feature of a number of pathological conditions such as asthma, rhinitis, eczema and parasitic infections ((see Bousquet, J. et al. N. Eng. J. Med. 323: 1033-1039 (1990) and Kay, A. B. and Corrigan. C. J. Br. Med. Bull. 48:51-64 (1992)). In asthma, eosinophil accumulation and activation are associated with damage to bronchial epithelium and hyperresponsiveness to constrictor mediators. Chemokines such as RANTES, eotaxin and MCP-3 are known to activate eosinophils ((see Baggiolini, M. and Dahinden, C. A. Immunol. Today. 15:127-133 (1994), Rot, A. M. et al. J. Exp. Med. 176, 1489-1495 (1992) and Ponath. P. D. et al. J. Clin. Invest., Vol. 97, #3, 604-612 (1996)). However, unlike RANTES and MCP-3 which also induce the migration of other leukocyte cell types, eotaxin is selectively chemotactic for eosinophils ((see Griffith-Johnson, D. A et al. Biochem. Biophy. Res. Commun. 197:1167 (1993) and Jose, P. J. et al. Biochem. Biophy. Res. Commun. 207, 788 (1994)). Specific eosinophil accumulation was observed at the site of administration of cotaxin whether by intradermal or intraperitoneal injection or aerosol inhalation ((see Griffith-Johnson, D. A et al. Biochem. Biophy. Res. Commun. 197:1167 (1993); Jose, P. J. et al. J. Exp. Med. 179, 881-887 (1994); Rothenberg, M. E. et al. J. Exp. Med. 181, 1211 (1995) and Ponath. P. D. J. Clin. Invest., Vol. 97, #3, 604-612 (1996)).
Glucocorticoids such as dexamethasone, methprednisolone and hydrocortisone have been used for treating many eosinophil-related disorders, including bronchial asthma ((R. P. Schleimer et. al., Am. Rev. Respir. Dis., 141, 559 (1990)). The glucocorticoids are believed to inhibit IL-5, IL-3 mediated eosinophil survival in these diseases. However, prolonged use of glucocorticoids can lead to side effects such as glaucoma, osteoporosis and growth retardation in the patients ((see Hanania N. A et al., J. Allergy and Clin. Immunol., Vol. 96, 571-579 (1995) and Saha M. T. et al, Acta Paediatrica, Vol. 86, #2, 138-142 (1997)). It is therefore desirable to have an alternative means of treating eosinophil related diseases without incurring these undesirable side effects.
Recently, the CCR-3 receptor was identified as a major chemokine receptor that eosinophils use for their response to cotaxin, RANTES and MCP-3. When transfected into a murine pre-.beta. lymphoma line, CCR-3 bound eotaxin, RANTES and MCP-3 and conferred chemotactic responses on these cells to eotaxin, RANTES and MCP-3 ((see Ponath. P. D. et al. J. Exp. Med. 183, 2437-2448 (1996)). The CCR-3 receptor is expressed on the surface of eosinophils, T-cells (subtype Th-2), basophils and mast cells and is highly selective for eotaxin. Studies have shown that pretreatment of eosinophils with an anti-CCR-3 mAb completely inhibits eosinophil chemotaxis to eotaxin, RANTES and MCP-3 ((see Heath H. et al. J. Clin. Invest., Vol. 99, #2, 178-184 (1997)). Applicants' copending U.S. patent application Ser. No. 09/134,013, filed Aug. 14, 1998 discloses compounds that are CCR-3 antagonists and inhibit eosinophilic recruitment by chemokine such as eotaxin.
Therefore, blocking the ability of the CCR-3 receptor to bind RANTES, MCP-3 and eotaxin and thereby preventing the recruitment of eosinophils should provide for the treatment of eosinophil-mediated inflammatory diseases.
The present invention concerns novel 4-aroylpiperidine analogs which are capable of inhibiting the binding of eotaxin to the CCR-3 receptor and thereby provide a means of combating eosinophil induced diseases, such as asthma.